Litchfield
is about to get a new arrival. Oscar-winning actress Mary Steenburgen
revealed on Twitter that she will be joining the Netflix dramedy Orange Is the New Black for season 3. In addition, several notable recurring stars have been promoted to series regulars.

SPOILER WARNING: This article contains plot details about Orange Is the New Black season 2.

Steenburgen revealed nothing about her role, simply saying that she was about to go to a wardrobe fitting, refusing to say whether she'll be in orange or black. Given the ending of season 2, there's definitely room for a new inmate, but also room on the prison staff.

Besides Steenburgen's casting, Orange Is the New Black has also many prominent guest star. Dascha Polanco, Selenis Leyva, Samira Wiley, Adrienne C. Moore and Nick Sandow have all been upped to series regular status for season 3. Respectively, they play pregnant inmate Daya Diaz, head of the kitchen staff Gloria Mendoza, Taystee's BFF Poussey Washington, the always outspoken Black Cindy and prison administrator Joe Caputo.

Besides those five promotions, Laura Prepon will return as a full-time series regular in season 3 as Piper's lover Alex Vause after being bumped down to a guest star in season 2.

None of these casting changes are that surprising as they have all been integral parts of the series since the start. It especially makes sense for Sandow, whose character got a promotion at the end of season 2 to assistant warden, and Prepon, whose Alex got busted on a parole violation (set up by Piper) and will most likely be coming back to Litchfield as an inmate.

It may be slightly confusing, but with such a large ensemble, Orange Is the New Black often blurs the lines between series regulars and guest stars. In season 1, there were only six credited series regulars: Taylor Schilling as Piper, Prepon as Alex, Kate Mulgrew as Red, Michelle Hurst as Miss Claudette, Jason Biggs as Larry and Michael J. Harney as Sam Healy. Four more inmates got promoted to series regular status in season 2: Uzo Aduba as Crazy Eyes, Danielle Brooks as Taystee, Natasha Lyonne as Nicky Nichols and Taryn Manning as Pennsatucky.

The expanding series regular cast speaks to the success of Orange Is the New Black, which recently launched its entire second season on Netflix.